-# FORTH
+# forth.jl
+
+A hobby implementation of a FORTH-like system atop the Julia scientific
+computing language. It will almost certainly never be useful for any purpose
+besides that which it has already fulfilled: forcing me to think quite
+carefully about how forth works.
+
+This package owes a massive debt to the existence of the literate programming
+project [JonesForth] (https://rwmj.wordpress.com/2010/08/07/jonesforth-git-repository/),
+which was an amazing read. To a large degree my package is simply a port of
+that project from x86 assembly + forth to julia + forth, although the mapping
+is in a few places non-trivial due to the fact that julia is a high level
+language. A huge proportion (say 80%) of the library code in src/lib.4th is
+directly copied from JonesForth. (The fact that it was possible to reuse this
+code was satisfying in its own right!) I've added some additional core
+definitions and modified some of the others to be a little bit closer to the
+behaviour of ANS forth (or at least FORTH 83).
+
+There's quite a lot to say about the implementation, especially due to its
+high-level grounding, but that will have to wait for another time.
+
+## Installation
+
+forth.jl is not (and probably will never be) a registered julia package. To
+install it, you will therefore need to use the following command:
+
+ julia> Pkg.clone("https://github.com/tgvaughan/forth.jl")
+
+## Usage
+
+To start the interpreter/compiler running, simply enter the following at
+the julia prompt:
+
+ julia> import forth
+ julia> forth.run()
+
+The first thing the interpreter will do is compile the core definitions in
+the library file. Once this is complete you can start entering forth commands:
+
+ : star 42 emit ;
+ ok
+ star
+ * ok
+
+Notice that unlike other forths, forth.jl echos a newline after reading each
+line of standard input. This is an unfortunate side-effect of the way that
+I've implemented EXPECT. Hopefully I'll be able to fix this in future.
+
+There's an example Mandelbrot Set drawing program included in the examples
+directory. To run it, you'll have to locate this directory on your system (its
+location depends on what OS you happen to be using and how julia is installed).
+Once found, use the INCLUDE word to compile its definitions. For example, on
+my system I can run the example in this way:
+
+ include /home/tim/.julia/v0.4/forth/examples/mandelbrot.4th
+ Enter 'mandel' to draw the Mandelbrot Set. ok
+ mandel
+ *
+
+ **
+ ********
+ *********
+ *****
+ *** ********************
+ ****************************** ****
+ **********************************
+ ***************************************
+ ********************************************
+ ** * *******************************************
+ ************* *********************************************
+ ****************** ********************************************
+ ******************* ********************************************
+ ** * * *******************************************************************
+ ******************* *******************************************
+ ***************** ********************************************
+ ************* ********************************************
+ ** * ********************************************
+ ********************************************
+ **************************************
+ ***********************************
+ ****************************** ****
+ ** ********************
+ *****
+ *******
+ *********
+ **
+ ok
+
+## License
+
+This package is free software and is distributed under version 3.0 of the GNU
+General Public License, which may be found in the file LICENSE in this
+directory.
The Lambda Lab / projects / forth.jl.git / blobdiff